Radio receiving device



March 18, 1941. V H, PENNER 2235,040-

RADIO RECEIVING DEVICE Filed Aug. 24, 1958 From, Direct Ccwrmb J'Lgpplg[m enfor llams firmer Jffawwgy Patented Mar. 18, 1941 UNITED STATESPATENT OFFICE RADIO RECEIVING DEVICE.

Lorenzweg, Germany Application August 24, 1938, Serial No. 226,456 InGermany August 28, 1937 3 Claims.

The present invention relates to radio receiving devices, and morespecifically to improvements in or relating to the accommodation of thepower consumption to the eifective load particularly in broadcastreceiving apparatus where the effective load customarily corresponds tothe output volume in form of acoustic waves.

It is well known to equip broadcast receiving devices with means foradjusting the output amplitude so as to provide the possibility ofadjusting the volume at will. Little attention has heretofore been paidto the possibility to simultaneously decrease the power consumption withvolume decrease. In fact, arrangements exist which employ some kind ofeconomizer circuits but such arrangements are not well adapted tosatisfy the requirements of modern technics. A further known arrangementselectively connects the loudspeaker either to the last or to the lastbut one tube so that the energy costs may be reduced by disconnectingthe final tube in cases that the incident high frequency energy is ofsufficient intensity, for instance on reception from a localtransmitter. Apart from the fact that the last but one tube of sucharrangements is dimensioned as a high power tube, the arrangementsuffers under the disadvantage that a changeover and thus a reduction ofthe current costs is possible only under such circumstances that theincident high frequency energy is of sufficient intensity.

In contradiction to the above described arrangement the presentinvention proposes to couple the means which are adapted to change theeffective load, that is the volume, with a device which accommodates thecurrent consumption to the effective load when this load is subjected tochanges. This device may either influence the anode voltage of the tubeor influence the grid biasing voltage so as to change the operatingpoint on the tube characteristic, or even to simultaneously influencethe anode potential and the grid potential. Preferably, the final tubeis subjected to such influence since the larger percentage of theeffective load is drawn by this tube.

The invention will be more readily understood from the followingdescription taken in conjunction with the accompanying drawing, thesingle figure of which shows a wiring diagram according to theinvention. In the drawing there are shown the two last tubes of abroadcast receiving device. I denotes a rectifier tube or diode whichdemodulates the high frequency oscillations received from an antenna orfrom a preceding high frequency amplifying stage. This rectifier diodeoperates into a resistance 2 to which the final tube 3 is coupledthrough a coupling condenser 4. The operating resistance 2 of the diodel is variable for the purpose of regulating the volume. The 5 glidecontact of this resistance is according to one feature of the inventionmechanically coupled with means which are adapted to simultaneouslyreduce the current consumption of the receiver. These means may as shownin the em- 10 bodiment according to the drawing comprise two additionalvariable resistances the glide contacts of which are simultaneouslydisplaced together with the glide contact of the resistance 2. One ofthe last mentioned resistances is a series 15 resistance 5 through whichthe anode current from an anode potential source and the choke coil 6flows and which in response to the desired volume dissipates more orless of the anode potential so as to reduce the overall efficiency of 20the final tube. A further resistance 1 has for its object tosimultaneously enhance the grid biasing voltage when the volume isdecreased. A decrease with respect to the volume is in the presentembodiment identical with downward dis- 25 placement of the glidecontacts. The resistance 1 together with the fixed resistance 8 serve ascathode resistance through which the direct anode current fiows and atwhich a potential drop is set up in the known manner for obtaining the30 grid biasing potential which is applied to the grid of the final tubeover the high ohmic grid resistance 9.

The invention is by no means limited to the embodiment heretoforedescribed and illustrated. 35 In many cases it might be suflicient toapply one of the above described possibilities, that is, to regulateeither the anode voltage or the grid biasing voltage.

It will be noted that the additional arrange- 4o ment for reducing thecurrent consumption as described in connection with the embodiment doesnot directly effect volume decrease. It may, for instance, be assumedthat the resistance RI is regulated from its position corresponding to a45 large volume to a position which corresponds to a low volume and thatthe two other resistances remain unchanged. When said last-mentionedresistances are then adjusted in the same sense onto a given point, thevolume will not decrease 50 and no distortion will be introduced butmerely a decrease of the current consumption is obtained.

It has already been pointed out that the present invention is notlimited to broadcast receiving devices. The invention is also applicable55 to television systems in which the efiective power occurs in thenature of an optical efi'ect, or in connection with printing telegraphor similar telegraph systems in which the effective power performs amechanical action.

What is claimed is:

1. A circuit for reducing the current consumption of volume controlamplifiers such as radio broadcast receivers upon adjustment fordecreasing the useful output, comprising a final voltage amplifier stagehaving a grid and plate, control means for adjusting the useful outputof said stage, and a device mechanically coupled to said control meansfor concurrently regulating the grid bias and plate potentials of saidstage with said control means to correspondingly control the currentconsumed by the amplifier.

2. A circuit according to claim 1 in which said device comprises anadjustable resistance in the anode circuit of the final amplifier stage.

3. A circuit in accordance with claim 1 in which said device comprisesan adjustable cathode resistance through which the anode current flowsand to which the grid is connected, Whereby the grid biasing potentialis increased as the output volume of said system is decreased.

HANS PENNER.

